I buy a lot of Yealink Products. Over 200+ phones this year alone via my Vendor. This is the very first time I have found the need to deploy the WF40 WiFi adapter. The results so far are very disappointing and inconsistent.

The long and short of it is this . . . . of 3 brand new T46S phones all running exactly the same Firmware Version of 66.81.0.110 & Hardware Version 66.0.0.128.0.0.0, two of the phones reported the "No Wi-Fi Adapter Found". Luckily for the customer and quite by accident the third phone recognized the WF40 Adapter and easily configured. All Phones had no issues with the BT40 Bluetooth headset confirming it wasn't a faulty USB/hw issue. I tired other (older/lower) FW levels to no resolve.

Features > Supports Yealink SIP-T27G/T29G/T46G/T48G/T46S/T48S/T52S/T54S - For T48G: upgrade to the version of 35.80.0.95 or higher - For T29G/T46G/T46S/T48S: upgrade to the version 81 or higher - For T27G: upgrade to the version of 69.81.0.90 or higher